Host-specific assembly of sponge-associated prokaryotes at high taxonomic ranks

Georg Steinert,Sven Rohde,Claudia Blaurock,Dorte Janussen,Peter J Schupp

doi:10.1038/s41598-017-02656-6

Abstract

Sponges (Porifera) are abundant and diverse members of benthic filter feeding communities in most marine ecosystems, from the deep sea to tropical reefs. A characteristic feature is the associated dense and diverse prokaryotic community present within the sponge mesohyl. Previous molecular genetic studies revealed the importance of host identity for the community composition of the sponge-associated microbiota. However, little is known whether sponge host-specific prokaryotic community patterns observed at 97% 16S rRNA gene sequence similarity are consistent at high taxonomic ranks (from genus to phylum level). In the present study, we investigated the prokaryotic community structure and variation of 24 sponge specimens (seven taxa) and three seawater samples from Sweden. Results show that the resemblance of prokaryotic communities at different taxonomic ranks is consistent with patterns present at 97% operational taxonomic unit level.

Highlights

Marine sponges (Porifera) are important benthic filter feeding organisms, which inhabit a large range of ecosystems, from the deep sea to continental shelves and shallow reefs, to tropical, temperate and polar regions[1]
Quantification of prokaryotic cell numbers in sponges provides a differentiation of high microbial abundance (HMA) and low microbial abundance (LMA) sponges[12], while parallel sequencing technologies emphasized the apparent importance of host identity on prokaryotic composition and diversity[2, 8, 13,14,15]
Recent quantitative approaches demonstrated divergent distributions of certain prokaryotic taxa that belong to sponge-associated phyla such as Chloroflexi, Actinobacteria, Cyanobacteria, and Poribacteria between HMA and LMA sponges[16,17,18,19]

Summary

Introduction

Marine sponges (Porifera) are important benthic filter feeding organisms, which inhabit a large range of ecosystems, from the deep sea to continental shelves and shallow reefs, to tropical, temperate and polar regions[1]. While different sponge-species apparently possess these specific dominant prokaryotic phyla, little is known whether the observed beta-diversity patterns (i.e., community variation among individual sponge hosts, here defined as local habitats of prokaryotic alpha diversities) are consistently detectable across taxonomic ranks ranging from OTU to phylum level. In the present study we investigated whether prokaryotic 16S rRNA diversity patterns at high taxonomic ranks were specific and meaningful for the sponge-associated microbiota. We hypothesize that even at this small scale (i.e. phylogenetically divergent sponge samples collected from the same locality), patterns of prokaryotic beta-diversity might reflect the putative functional traits and adaptation of sponge-specific deep branching prokaryotic lineages at high taxonomic ranks. For the analysis of beta-diversity among different sponge hosts the available community abundance data was collapsed at OTU level (97% sequence identity) and converted into high taxonomic ranks ranging from species to phylum level. We used indicator species analysis to assess the host-specificity of sponge-associated prokaryotic communities

Methods

Results

Conclusion